Upcoming

Stargate Atlantis: The Complete Fifth Season (and also the final season) is available for pre-order. It'll be out June 30, 2009.

Supernatural: The Complete Fourth Season is available for pre-order. No date yet for its release.

Fringe Season 1 is available for pre-order.

Kings - Season One will be available later this year.

Battlestar Galactica: Season 4.5 is available for preorder from Amazon.com.

Battlestar Galactica Season Three will be available March 25, 2008.

Battlestar Galactica: Season Three at Amazon.com (currently $38.99 - subject to change)

The Showtime original series, The Tudors, will be available on DVD January 8th, 2008.
The Tudors - Season 1

Here's the product description from Amazon.com:

Rumor has it that just before Christmas, you can pick up a copy of High School Musical 2! Disney apparently will be releasing the DVD on December 11th.

Pirates of the Caribbean - At World's End (Two-Disc Special Edition)

Releases on December 4, 2007.